Clamp for wheelchair lift



y 15, 1969 l. B. RACHMAN CLAMP FDR WHEELCHAIR LIFT Filed April 29, 1968 AVV'IVTflP. lSADORE B. RACHMAN tats 2 Claims ABSTRACT OF THE DISCLOSURE A clamp for a wheelchair lift wherein the clamps engage an upright part of the wheelchair and are simultaneously displaceable in opposite horizontal directions for quick connect and disconnect operation.

This is a continuation-in-part of application Ser. No. 681,437 filed Nov. 8, 1967.

This invention relates to a clamp for a wheelchair lift. More particularly, this invention relates to a quick connect and disconnect clamp used on a wheelchair lift.

It has been reported that there are literally hundreds of thousands of non-ambulatory persons in wheelchairs. To transfer these persons to dental or barber chairs may be hazardous to the patients health, painful or at least uncomfortable. Yet it is necessary that persons confined to wheelchairs provide many of the services that healthy persons take for granted. Dental care presents a particularly difiicult problem. Patients with neurologic diseases, poliomyelitis, muscular dystrophy, multiple sclerosis, paraplegia, arthritis, broken bones, those who have had cerebral vascular accidents, and others who may need dental care, cannot be moved easily into a conventional dental chair. If these patients are to be treated in wheelchairs, the dentist must assume a strained and contorted position while rendering therapy. This results in extreme fatigue, and hence a reduction in the dentists ability to render care.

Devices for transferring patients to a dental chair or the like have been previously suggested. For example, a trapeze bar has been suspended from the ceiling over the chair. This bar is helpful for patients with strong arms, such as paraplegics, who can lift themselves from their wheelchair and swing themselves into the dental chair. Elderly patients and others, however, are not capable of this effort. Thus, lifting devices have to be provided. Lifting devices function well where the patient can be moved. But more often than not, patients confined to wheelchairs are best not moved at all.

As a solution to this problem, it has been suggested that dental chair bases be modified so that a wheelchair can be positioned thereon. The present invention is related to this latter type of device and is an improvement thereon. In patent application Ser. No. 681,437 filed Nov. 8, 1967, there is described an invention wherein the wheelchair and patient may be raised, tipped backward, or lowered to the most favorable working position for the dentist, barber or the like, and with the least discomfort and inconvenience to the patient. The present invention is an improvement on the wheelchair lift described in the aforesaid patent application in that it provides a quick connect and quick disconnect for the wheelchair which may be effected with ease.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities down.

3,455,455 Patented July 15, 1969 FIGURE 1 is a side elevational view showing the wheelchair in position on a wheelchair lift.

FIGURE 2 is a partial elevational view of the wheelchair lift taken along the line 2-2 in FIGURE 1.

FIGURE 3 is a partial rear view of the wheelchair lift shown in FIGURE 1.

FIGURE 4 is a sectional view of the wheelchair lift taken along the line 44 in FIGURE 2.

FIGURE 5 is a side view of the Wheelchair lift shown in FIGURE 1 with a portion of the chair partially broken away.

FIGURE 6 is an exploded perspective view of the clamping elements.

Referring now to the drawing in detail, wherein like numerals indicate like elements, there is shown in FIG- URE 1 a wheelchair lift designated generally as 10.

A wheelchair 12 is shown positioned on the lift 10. Wheelchair 12 may be regarded as representative of the many types of wheelchairs presently on the market. Different wheelchairs have different types of designs depending upon the medical function which they are required to support. Wheelchair 12 shown herein includes features which are more or less common to most wheelchairs. Thus, it includes a pair of large rear wheels 14 which are rotatably fixed to the frame 16 and a pair of small diameter front wheels 18 which are preferably of the caster type. The frame 16 is collapsible and includes a fabric-type seat 20. Frame 16 also supports the footrest 22. The back rest 24 is also preferably made of a fabric and extends across the uprights 25 and 27 which form the rear portion of the frame 16. Extending rearwardly from the uprights 25 and 27 are a pair of handles 26 with appropriate handle grips 28 fixed thereon. A headrest designated generally as 29 is fixed to the handles 28 in the manner described in the aforesaid patent application Ser. No. 681,437.

The lift 10 includes a horizontal platform 30 which comprises a pair of angle members 32 positioned with their flanges extending laterally outward. Only one of the angle members 32 is shown. However, both angle members are rigidly connected by transverse spacers which are welded or otherwise attached to the angle members. The spacing between the upright flanges of angle members 32 is slightly less than the inner width between the wheels 14 of the chair 12. As thus positioned, the angle members 32 acts as a guideway for the rear wheels 14 whereby the chair may be accurately backed on to the platform 30 formed by the angle members 32.

It should be noted that only the rear wheels 14 are supported on the platform 30. It has been found that the combination of the clamping member described herein and the foreshortened platform 30 is sufficient to safely fix the chair 12 in position during the operation of the lift 10.

The platform 30 is fixed to a vertical member 46 which comprises a pair of upright plates 48 and 50 which are attached to the angle members 32 by any conventional method such as a weld. Plates 48 and 50 are connected adjacent their upper and forward sides by a backing plate 52 which extends between and is fixed to them by any conventional method such as a weld. Blocks 54 and 56 are welded to the backing plate 52 at a position where the uprights 25 and 27 may be brought into abutment with resilient pads fixed to their exposed surfaces as by an adhesive.

The entire platform 30 and vertical member 46 are pivotally supported on a conventional elevating mechanism 76. Elevating mechanism 76 may be of the type ordinarily used for dental and barber chairs but with all of the superstructure stripped away. Since such lifting mechanisms are well known and available on the open market, there is no necessity to describe them in detail.

In place of the superstructure for a conventional dentist or barber chair, the uprights 48 and 5% are pivotally connected to the elevating mechanism 76 by a pair of pins 80 which extend through upright plates 48 and 50' and engage a pivot plate (not shown) on the elevating mechanism 76. This is the only connection between the vertical member 46 and the elevating mechanism 76. Accordingly, the vertical member 46 and platform 30 can pivot relative to the elevating mechanism. Such pivot function is accomplished by a hydraulic cylinder and lever mechanism 91 which is fixed to the elevating mechanism 76 at one end and connected to the vertical member 46 at the other end. By operation of the lever 95, the vertical member 46 and platform 30 are caused to pivot. A more detailed description of this function is provided in the aforesaid patent application.

The wheelchair 12 is maintained in position on the platform 30 with the uprights 25 and 27 against the pads on blocks 54 and 56 by engaging the uprights 25 and 27 with a pair of clamps 62 and 64-. Clamps 62 and 64 are identical, but of opposite hand. Accordingly, a description of the clamp 62 will suffice as a description of the clamp 64.

As best shown in FIGURE 5, clamp 62 consists of a block 66 having an integral tongue 68 extending therefrom. The block 66 has a greater width than the tongue 68 and is adapted to have a face thereof 70 positioned in abutment with the guide bar 72. When the face 70 of block 66 is abutted against the face of guide bar 72, the tongue 68 is spaced away from it thereby providing a generally U-shaped channel for receiving the upright 25. Since the uprights 25 and 27 are normally tubular, the corner between the block 66 and the tongue 68 is normally rounded over approximately the same diameter. If desired, a resilient pad 74 can be cemented or otherwise fixed to the interface of tongue 68 and block 66.

A pair of pins 76 and 78 extend through the block 66 and project from face 70. These pins are long enough to extend through a slide in a slot 80 formed in guide bar 72. The pins 76 and 78 are threadedly engaged in openings 81 and 83 in the slide block 82. Thus, the slide block 82 cooperates with the pins 76 and 78 to retain the clamp 62 on the guide bar 72. The pins 76 and 78 are normally drawn up into the threaded openings 81 and 83 sufficiently to firmly retain the clamp 62 on the guide bar 72 but still permit it to slide freely along the horizontal slot 80.

As best shown in FIGURES 2, 3 and 4, the clamp 64 is the same as clamp 62 except that it is of opposite hand. Accordingly, the structure associated with it has been designated by the same but primed numbers.

As best shown in FIGURES 2 and 4, the clamps 62 and 64 retain the uprights 25 and 27 in position against the blocks 54 and S6 and the guide bar 72 by being forced into an overriding position as shown in FIGURE 4. The clamps 62 and 64 are simultaneously moved into the sliding position by a pivot-link mechanism comprising a rotatably mounted displacement member in the form of a disc 90. Disc is pivotally connected to the guide bar '72 by pin 92 and may be caused to rotate by operating the arm 94 which extends radially therefrom. If desired, the arm 94 may be provided with a handle grip 96.

As shown in FIGURE 3, a link 98 is connected between the clamp 64 and the disc 90. In a like manner, a link 100 is connected between the disc 90 and the clamp 62. As shown in FIGURE 6, the link 100 is threadedly engaged in the opening 102 in the block 82. In a like manner, the link 98 is threadedly engaged in a similar opening in the block 82. The links 98 and 100 are eccentrically connected to the disc 90 at diametrically opposite points radially spaced from the pin 92. Accordingly, rotation of the disc 90, displaces the links 98 and 100 and hence simultaneously forces the clamps 62 and 64 to slide in the slots 80 and 80.

I claim:

1. A wheelchair lift comprising a normally horizontal platform for supporting wheelchair wheels, a normally vertical member fixed to said platform and extending upwardly from it, hydraulic means for raising said platform and vertical member, said vertical member being pivotally connected to said hydraulic means, hydraulic means for tilting said platform and vertical member about said pivotal connection, clamp means on said vertical member for engaging a wheelchair and fixing it in position, said clamp means including guide means, a pair of clamps slidingly disposed on said guide means for simultaneous horizontal displacement into and out of engagement with a portion of a wheelchair, and means for simultaneously displacing said clamps in opposite direction.

2. A wheelchair lift in accordance with claim 1 wherein said guide means is a guide bar having a pair of slots therein, said clamps being slidingly disposed in said slots,'and said means for simultaneously displacing said clamps in opposite direction comprises a rotatably mounted displacement member, and a pair of links connecting said displacement member to said clamps, said links being eccentrically connected to said displacement member relative to its center of rotation.

References Cited UNITED STATES PATENTS 482,520 9/1892 Field et al. 297 325 2,733,825 2/1956 Evans 21470l XR 2,898,872 8/1959 Hastings.

GERALD M. FORLENZA, Primary Examiner FRANK E. WERNER, Assistant Examiner U.S. c1. XR. g14 7o1; 297-133 

